Isaiah 51:13

And forgettest the Lord Not in the sense of apostatising from Him (as ch. Isaiah 17:10 and often), but of failing to realise His omnipotence as the Creator of all things (see ch. Isaiah 49:14).

that hath stretched forth the heavens &c. Cf. Isaiah 40:22; Isaiah 42:5; Isaiah 44:24; Isaiah 45:12.

and hast feared … day Better as R.V. and fearest continually all the day. The oppressoris of course the Chaldæan Empire (see ch. Isaiah 47:6), a proof that this part of the book was not written after the fall of Babylon.

as if he were ready to destroy R.V. when he maketh ready to destroy; lit. "aims (his arrow) to destroy," the verb being used technically of an archer directing his arrow; so Psalms 21:13, cf. Psalms 7:13; Psalms 11:2.

and whereis the fury of the oppressor? Cf. ch. Isaiah 33:18. The question gives a weak ending to the verse, and indeed both in this clause and the preceding the soundness of the text is doubtful.